Floor sanding machine



NOV. 25, 1952 ROSE FLOOR SANDING MACHINE Filed Feb. 14, lso

5 Sheets-Sheet 1 w m w R O T N E V N (Q 9634 4 J l 4k&

ATTORNEYS 7 Nov. 25, 1952 D. M. Ro-SE 2,618,914

FLOOR SANDING MACHINE Filed Feb. 14, 1950 5 Sheets-Sheet ,2

l I! w 39 INVENTOR- Danz] Maria n Fa e W102, Ja

ATTORNEY NOV- 25, M. ROSE I FLOOR SANDING MACHINE I Filed Feb. 14, 1950 5 Sheets-Sheet 5 g Byi uma i ATTORNEY? S F2222 J/OrZZIZ jiase- Nov. 25, 1952 D. M. ROSE 4 FLOOR SANDING MACHINE Filed Feb. 14, 1950 5 SheetsSheet 4 I mvgmon 173mb] [Horton Rose ATTORNEYS D. M. ROSE FLOOR SANDING MACHINE Nov. 25, 1952 5 Sheets-Sheet 5 Filed Feb. 14, 1950 plllll I I N VE NTOR Danie? Mar/52730.90

ATTORNEYS Patented Nov. 25, 1952 UNITED STATES PATENT OFFICE FLOOR SANDING MACHINE Application February 14, 1950, Serial No. 144,145

10 Claims.

This invention relates to improvements in floor sanding machines of the character used for cleaning and finishing hardwood floors, although it is also adapted for resurfacing any desired floor surface.

The usual method of cleaning hardwood floors, generally in use heretofore, has involved the operation of a rotating drum sander. Such a machine actually causes defects to be imparted to the floor surface. In preparing matched flooring, the finishing machines ordinarily in use apply to the surface eleven knife marks per inch that are spaced uniformly and evenly according to the mechanical rate of feed and fixed spindle speed. In attempting to remove such marks and variations in matching, a drum sander has a line contact with the floor surface and replaces the variations in the initial floor finish by uneven Waves from the sanding machine drum. Another objection to the ordinary drum type of sanding machine as in use heretofore involved the outside bearings thereof and drum diameter which keep the sanding surface away from the baseboard, to keep the drum from marring the surface of the base, so far that there is a border of five or six inches left around the circumference of the floor surface that is either not cleaned at all or must be cleaned by hand.

One object of this invention is to overcome the objections heretofore mentioned in a rotating drum sanding machine, by providing for uniform surfacing operations on a floor surface which will eliminate the uneven waves resulting from the rotation of the drum in its line contact with the floor surface, and will provide for a cleaning operation substantially to the periphery of the floor surface as well as maintain the floor surface in an even, smooth, unbroken parallel plane.

Another objection that has been encountered in the use of rotating drum sanding machines involves the operation thereof by an electric motor, and, because of the character of the drum and the need for an air vacuum system, they are noisy and dirty and spread dust throughout the home in which the surfacing operation may be carried out. The operation of the drum and the vacuum system requires an electric motor of considerable power, which usually makes necessary a temporary special installation of electrical equipment that adds considerably to the cost of the operation, is dangerous due to Worn insulation, and objectionable because of the necessity for dragging the equipment throughout the portion of the house in which the surfacing operation is to be carried on.

A further object of the invention is to overcome these objections to the drum type sanding machine, by providing for the operation thereof by means of a self-contained power unit, such as a gasoline engine, which operates the sanding elements with a uniform rubbing motion without spreading dirt and dust through the room, but leaves this on the floor where it cannot contaminate other objects and portions of the room in which the sanding operation is performed.

When the rotating drum type of sanding machines in use heretofore, it was necessary to use the said paper until it becomes dull and lacks effective surfacing operation, but the changing of such paper, which is required frequently, consumes considerable time. The use of the new sanding surface produces a different effect from that obtained when the paper has become worn and dull, thus resulting in uneven sanding operations over different portions of the floor surface.

Still another object of this invention is to overcome these objections by providing for the gradual changing and/or reversing of the sand paper, thus presenting a continually changing sanding surface to the floor and keeping the surface in contact therewith and free of clogging, which has been another objection to the rotary drum type of sanding machine.

A still further object of the invention is to improve the construction of floor sanding machines to provide a construction which is practical for manufacture, may be handled readily when in use, and is eifective in accomplishing the desired surfacing operation in service.

These objects may be accomplished by providing a sanding head or a plurality of sanding heads, each of which, preferably, has a sand paper mounting adapted not only for holding the sand paper in position for surfacing operation, but also for gradually changing the sand paper surface as the sanding operation progresses. This is accomplished by a gradual feeding of the paper relative to the head, preferably back and forth as the machine is used, which is highly effective not only in presenting a new sanding surface to the floor, but also in keeping the sand paper clean and free from clogging. Moreover, it keeps the dirt on the surf-ace of the floor without throwing it up in the air, where it would be suspended thereby and would accumulate on other objects in the room.

It is preferred that a pair of sanding heads be used, mounted for reciprocating movement, respectively in opposite directions, whereby these would balance each other, and one would move forward when the other moves rearward, thus eliminating objectionable thrust by this counteracting operation which keeps the pressure and action from being transmitted to the operating mechanism and to the operator.

It is preferred that the sanding heads be operated by a self-contained power plant, such as a gasoline engine, which can impart a uniform action thereto without the necessity for having available expensive and objectionable auxiliary equipment, such as heavy voltage power lines, transformers, etc., as is required with the rotary drum sanding machines operated by electric motors, as generally in use heretofore. Moreover, gasoline is available almost anywhere and can be transported readily, if needed, so that the machine can be used in places where electric current is not available, especially in new houses under construction, as is often desired.

One embodiment of the invention is illustrated in the accompanying drawings, in which:

Fig. 1 is a side elevation of a fioor sanding machine embodying this invention;

2is a cross section therethrough on the line -2--2 in Fig. 6.;

Fig. 3 is a front elevation of the power end of the machine, partly'in section;

Fig. 3a is a detail side elevation of the floor wheel drive;

Fig. 4 is a partial top plan view thereof, with a part broken away, and taken substantially on the line '44 in Fig. 1;

Fig. 5 is a horizontal section therethrough substantially on the line 55 in Fig. 3;

Fig. '6 is a top plan view of the sanding head 'end of the machine;

Fig. 7 is a front end elevation thereof;

Fig. 8 is a detail perspective view, partly in section, of one of the ratchet cams;

Fig. '9 is a side elevation, partly in section, of one of the ratchet pawls;

Fig. 10 is a perspective view of a portion of one of the holding pawls'; and

Fig. -11 is a side elevation of one of the paper feeding ratchets.

The embodiment of the invention as shown in the drawings includes a power unit mounted for operation over the floor, which is adapted to actuate a sanding unit that is operatively connected. therewith. The machine is adapted for movement back and forth at any rate of travel from one side of a room to the other, and during such movement it is preferred that the sanding unit be operated to provide the desired sanding action on the floor surface.

The power unit of the machine is provided with a supporting frame structure which may be of fabricated design and assembled and secured in such relation as to support the operating portions of the power unit. As illustrated in Figs. -1 and 3, the frame structure includes a floor plate I having upstanding supports Zspaced on opposite sides of the longitudinal center thereof, and upon which supports is mounted a transverse supporting plate 3. The side supports 2 also carry on the upper ends thereof an elevated platform 4 upon which is secured an internal combustion engine 5. The engine 5 is shown as of a conventional construction, the details of which need not be described. However, any suitable power plant may be used, as desired, although it is preferred that this be self-contained rather than an electric motor, but the latter may be used, if preferred.

The engine 5 has a drive shaft 6 connected therewith, upon which drive shaft a pulley I is mounted. Extending from the pulley I is a belt 8 in driving relation with the pulley, and which belt extends downward over and around a pulley 9 on a counter shaft ID, as shown in Figs. 1 and 3. The counter shaft It extends to a speed-reducing gear unit, generally designated at ll, and which is supported upon the floor plate l.

Extending laterally from the unit I I is a shaft [2 having. a sprocket wheel I 3 thereon over which a sprocket chain l4 passes. At its opposite end the sprocket chain l4 extends about a sprocket wheel l5 mounted on a shaft Hi. The shaft it also carries a sprocket wheel i'i over which a sprocket chain is extends to a sprocket wheel IS. The sprocket wheel is is mounted on a cross shaft 20 that extends from side to side of the machine and is journalled in bearing boxes 2| supported on the frame of the power unit.

It will be apparent that the speed of the power shaft of the engine 5 is continuously reduced during the several driving steps mentioned, inasmuch as the drive of each of the belts and sprockets is from a small to a large pulley or wheel, in addition to the reduction in speed that is effected by the speed-reducing gear unit H, whereby the shaft 20 will be driven at a comparatively low speed.

The shaft 20 carries on opposite ends thereof a pair of crank wheels 22, which appear in Figs.

1, 3 and 4. These crank wheels 22 are shown in the form of enlarged discs, although other types of operating members may be used, as desired. Each of the wheels 22 is adapted for operating one of the sanding heads, as hereinafter described.

The power unit is adapted to-be supported on the floor surface by a pair of floor engaging wheels 23, one on each side of the machine. Each of the wheels 23 is mounted on a stub shaft 24, which shaft 24 is journaled in a bearing box 25 secured upon the floor plate I of the frame of the power unit. Thus, the supporting wheels 23 carry the power unit for movement back and forth over the floor surface at any desired rate of feed in either direction.

It is preferred that the wheels 23 be power driven. In the embodimentillustrated, each of the wheels 23,01 the stub shaft thereof, is shown as provided with a sprocket wheel 25 over which a sprocket chain 27 extends, thence around a sprocket wheel '28 mounted on a counter shaft2'9. The wheels 23 are separately driven, as shown in Fig. 3, from the opposite ends of the counter shaft 29.

The counter shaft '29 is supported by hearing boxes '30 within which it is journaled, which bearing boxes 30 are seated upon supporting arms 3! extending laterally from, and pivotally supported on a shaft 29 mounted on the supporting plate 3 of the supporting frame. A toggle 3i may be connected with the supporting arms '31 to adjust the position of the shaft 29 (-Fig. 3a). This toggle 31' is shown as adjustable by a hand screw 32'.

A friction gear wheel 32 has the hub thereof mounted on the counter shaft 29, preferably with a splined connection between the hub and shaft, as indicated generally at 33, so as to key the friction wheel 32 to the shaft while allowing for freedom of sliding movement of the wheel lengthwise relative to the "shaft.

The friction wheel 32 engages at its periphery with the face of a cooper-ating friction wheel 34, as shown in Figs. 3 and 5. The friction. wheel 34 is mounted on a shaft 35 journaled in bearings 35 at opposite ends thereof within the upstanding supports 2 of the frame structure. The friction wheel 32 may be shifted lengthwise of the counter shaft 29 to opposite sides of the axis of the shaft 35. When shifted to one side of the axis of said shaft 35, the friction wheel 32 and shaft 29 will be operated in one direction. When shifted to the opposite side of the axis of the shaft 35, the shaft 29 will be driven in the opposite direction. The speed of operation of the shaft 29 may be varied according to the distance from the axis of the shaft 35 that the friction wheel 32 is shifted. Any suitable shifting means may be used as is customary with change-speed gearing of the friction or other types, such as a yoke having a journaled connection with the hub of the friction wheel.

The friction wheel 34 bears at its periphery against a friction wheel 31- fixed on the drive shaft 6 of the engine. The friction wheel 31 is appreciably reduced relative to the diameter of the friction wheel 34, thereby effecting a reduction in speed from the drive shaft to the shaft 35 or the friction wheel 34 mounted thereon.

The floor engaging wheels 23 are driven by the sprocket chains 21 from the counter shaft 29, either forward or reverse according to the direction of rotation of the counter shaft. It is preferred that the machine operate continuously in one direction across the floor surface from one side of the floor surface to the opposite side,

when its direction of operation may be reversed by the operator manipulating the shifting yoke or other means for sliding the friction wheel 32 to the opposite side of the center axis of the driving friction wheel 34. By adjusting the toggle 3| the supporting arms 3| may be adjusted away from the friction wheel 34 to disengage the friction disc 32 therefrom and thereby stop the feeding movement of the floor wheels 23.

I have shown and described the use of a belt and sprocket chains forming driving connections between the several parts, and also friction gearing. These driving connections are preferred in one embodiment of the invention, but it is recognized that other types of driving connections may be used, as desired, and that other variations may be made therein for accomplishing the desired results.

The power unit of the machine is adapted for operating sanding heads, two of which are shown in side-by-side relation in Figs. 1, 2, 6 and '7, and

"are designated generally by the numeral 38.

from the frame base of the power unit of the -machine and are secured rigidly thereto, as by Welding. While separate inner guide bars 49 are shown, these may be combined in one member, if desired. The guide bars 39 and 49 form an enclosed path for the reciprocating movement of each sanding head 33 therein. The guide bars 39 and 49 provide protection from damage to the sanding block 41 and also prevent damage to the wall and baseboard due to reciprocating side and end motion of the block 41. This is a desirable action in addition to their function of holding .;;and guiding the sanding heads 39.

The floor plate I, as shown in Fig. 3, extends out to theguides 39 in order to be welded to the same, which plate also supports the bearings 25.

There are two rectangular slots cut in this plate I at the outer edges thereof to receive the iioor wheels 23 protruding through this plate to the floor. There is just enough clearance to allow the wheels to turn, and yet give the floor plate I a chance to extend out far enough to be welded to the guide rods 39. Then again, two rectangular recesses are cut out in the middle of this plate I to receive the guide rods 49 to be welded also to this plate I.

The outer ends of these bars 39 and 49 are connected together by a cross bar 4| pivoted at 42 to the bar 39, and which bar 4| has a detachable pin connection 43 with the bar 49. Thus, the cross bar 4| is pivoted to one of the guide bars and has a detachable connection with the other whereby, upon withdrawing the pin 43 and swinging'the connecting bar 4| outward, the sanding head 38 may be withdrawn therefrom.

The sanding heads 33 are adapted to be reciprocated in the guide path provided between the bars 39 and 49 by connecting rods 44, one for each sanding head. At one end, each connecting rod 44 is connected with a side of the sanding head 38 by a pin 45, which pin should be detachable from the head to permit removal of the latter from the machine. At the opposite end, the connecting rod 44 is pivotally connected at 49 with one of the crank wheels 22, these pivotal connections being out of phase with each other to counteract the thrust imposed by the reciproeating movement of the sanding heads, and whereby one head will be moved forward when the other head is moved in the opposite direction. This relation will be apparent from Figs. 4 and 5.

Each of the sanding heads is shown as including a block 41 which may be partially cut away, as shown in Figs. 2 and '1, if it be desired to reduce the weight thereof, or for other purposes. Supported upon opposite sides of the bearing block 41 at opposite ends thereof, are upstanding brackets 48, within which are journaled winding shafts 49 and 59. These winding shafts are in parallel relation above the block 41, and each of them may have a slot 5| or other means connected therewith for attachment of one end of a strip of sand paper 52 to the corresponding shaft. The bottom of the block 41 preferably is flat with the sand paper 52 bearing thereagainst throughout the area of the bottom of the block, so as to press uniformly the entire surface of the sand paper against the floor surface.

The strip of sand paper 52 is wound at its opposite ends upon the respective shafts 49 and 59 and extends therebetween down the sides and beneath the block 41, as shown in Fig. 2, with the exposed side of the sand paper at the bottom of the block adapted for surfacing operation against the floor surface to be refinished. Any suitable material other than sand paper may be used on the head 38, if desired, according to the treatment that may be applied to the surface.

It is preferred that the sand paper 52 be moved, step by step, during the operation of the head 38, so as to change continually the portion of the surface thereof that is in contact with the floor surface. This serves not only for cleaning the sand paper, but also presents a fresh clean surface thereof to the floor, whereby improved results are obtained and a more perfect finish.

As one means that may be used for accomplishing the step-by-step shifting movement of the sand paper 52, I have shown a ratchet device connected with each of the shafts 49 and 59 and so constructed that a shifting movement of the sand paper will be accomplished upon every other change in direction at or near the end of outward movement of the sanding head 38. It will be appreciated from Fig. 1 that each sanding head will be moved, first in one direction. and then in the opposite direction, for each revolution of the corresponding crank wheel 22, thus effecting movement of the sanding heads, respectively, in opposite directions.

In this embodiment, each of the shafts 49 and 50 is provided with a guide disc 53 at one side thereof, and a similar disc 54 at the opposite side thereof, which latter, however, has peripheral gear teeth 55 thereon. These discs 53 and 54, preferably, are secured to the corresponding shaft 49 or 50, whereby, upon engagement with the teeth 55, the connected shaft may be. locked against turning movement. A holding pawl 56 is shown in Figs. '7 and and is provided with teeth 51 in position for engaging the peripheral teeth 55 of the disc or'wheel 54. Thus, upon engagement of the holding pawl 56 with the teeth of the wheel 54, the latter is fixed in position and prevents rotation of the corresponding shaft.

The holding pawl 56 is provided with an elongated shank slidably mounted in guides 58 upon the supporting bracket 48 for vertical sliding movement of the holding .pawl, to cause the teeth 51 thereof to be moved into and out of engagement with the peripheral teeth 55 of the gear wheel 54. The motion of the pawl 55 is limited by stops 58' on the shank thereof. The lower end of the shank of the holding pawl 55 is pivotally connected at 59 with one arm of a bell crank 50, the other arm of which carries a ratchet pawl Bl As shown in Fig. 9, the pawl El has a tooth thereon in position for engagement, selectively, with the teeth 55 of the gear wheel 54. This pawl is pivoted at 62 on the bell crank 50 and has a coiled spring 63 connected with the pawl in such position as to act normally to hold the pawl in engagement with the teeth 55, except when the pawl is moved sufficiently far toward the left in Fig. 9 as to shift the spring to the opposite side of the center axisof the pivot 62, when the spring would hold the pawl out of engagement with the ratchet wheel. A stop 64 may be provided for engagement by 2. lug on the pawl 6!, so as to limit the swinging movement of the pawl away from the wheel.

Each bell crank 55 is pivotally supported on a pin 66 projecting laterally from the block 41 of the sanding head, as shownin Fig. 11 and errtending through a slot (Fig. 11-) in the bell crank 60 to provide a sliding pivotal motion. Normally, the bell crank 50 is turned in a clockwise direction, as viewed in Fig. 11, about the pivot 65 by a coiled spring 61 connected with the bell crank through the pivot pin 59, and extending from the latter to a connection at a side of the block 41.

Upon upward shifting or rocking movement of the bell crank 60 about the pivot pin 65, against the tension of the spring 61, the bell crank will cause upward movement of the pawl 56, disento wind the sand paperon the shaft connected therewith.

This shifting movement or the bell crank-.50 is accomplished by dog'sGB, 68', each of whichis pivotally attached to a pivot pin 65 on the bell crank 60, but ecoentrically of the pin. The dogs 68, 68 have a notch in one side thereof in position for engagement with a pin 69 carried by a portion of the bell erankfifl beneath the pivot 65. Upon positive swinging movement of the dogs 68-, 68' in one direction (counter clockw-ise, as viewed in Fig. 1 the bell crank '60- willbe rocked by a pivot action 'on the 'pin'66 attached to the bell crank on the outward stroke of the block 41 only; as on the return stroke the dogs 58, 6-8 trip over the name 10-.

This action of the dogs 68, 68' will be caused by cams 70, 10', each of which has an inclined face in position for engagement with the lower end of the dog. The cams 10, T0 are secured't'o the guide rod 39 in an adjusted position relative thereto by a clamping screw or bolt H, as shown in Figs. 1 and 8. The earns l0, 10' have a portion thereof in overlapping relation with a portion of theguide rod 39, or extend into a groove therein, and the guide rod 39 is slotted at 12 to provide for lengthwise adjustment of the cams relative to the guide rod upon-loosening of the screw II.

As shown in Fig. l and as mentioned above, the respective shafts 49 and50 are provided with ratchet devices of the character described, each of which ratchet device'sfun'ctions in the manner described above, except that one is turned in the opposite direction from the other, as shown, whereby one of the pawls 6! will be out of engagement with its corresponding ratchet wheel 54 when the other is in engagement therewith, and thereby causing a feeding movement of the sand paper 52 by the shaft connected with the sand paper at one end, the oppositeshaft'being free upon disengagement of its holding pawl-5'6 to allow unwinding of the sand paper onto the other shaft.

For instance, in Fig. 2, if the paper is-be'in'g wound onto the shaft 49, the pawl '61 of that shaft will be in engagement with-the teeth 550i the ratchet wheel 54 thereof, while the pawl- 61 of the shaft 50 will be out of engagementwith its ratchet wheel. Consequently, upon engagement of the dog 58 corresponding with the shaft 45 with its cam 15, the ratchet device will be operated to rotate the shaft-49 through one step, thus winding the strip of sand paper 52 on the shaft 49 and gradually changing the sand paper beneath the block 41-.

Since the sand paper will be shifted one step for each outward stroke-of the sanding head, it is apparent that a gradual shifting of the sand paper will take place during the operation of the machine, which will-be continuously inone direction so long as the same pawl BI is in en'- gagement with its ratchet wheel. When the operator desires to change the direction of feeding movement of the sand paper on each of the sanding heads, it is necessary merely to shift the pawl 6| in' engagement with the ratchet wheel to move it out of engagement therewith, and to shift the other pawl 61 into engagement with its ratchet wheel. This may be-done manually by a tipping action of each respective pawl,-

as will be apparent from Figs. -2 and '9.

As the sanding head is reciprocated in its movement, the dogs 88, 6'8 will ride-over the cams 10, 10' to be located on the opposite sides thereof from the positions shown in Figs. 1 and 2. Then, upon outward movement of one of the heads, the lower ends of the dogs 68, 68' will be pressed by the inclined faces of the cams I0, against the pins 69, which pressure will be sufficient to cause a rocking motion of the bell cranks BI, 60' about the pivots 66. This is the action that will rock the bell cranks in a direction to cause a feeding action on the corresponding shaft 49 or 50, according to which of the pawls BI is in engagement.

What actually is accomplished by this mechanical arrangement in unison action are, to hold the sandpaper in tension beneath the sanding-head 38 in both directions of movement to prevent the buckling and crumpling of the same; also, and at the same time, compensating for the slack usually created by the same amount of rotation caused by feeding between two rolls of constantly varying diameters.

It is possible to remove either of the sanding locks from the machine very readily and quickly merely by removing the wrist pin 45 and opening the end bar 4| upon the removal of the pin 43. This makes it possible to remove the block either for replacing the sand paper or to substitute an operating block of a different type, and permits the exchanging of different weight blocks that are required by different grits of sandpaper for economical sanding action. Then, upon re-inserting the block or applying a different block and connecting this at 45, the machine can be put into operation again very quickly.

It is also possible to substitute for the sanding blocks a block of a different type or for a different finishing operation. For instance, to remove the filler from a floor, blocks can be used that have been wrapped in cloth instead of sand paper, whereby this machine makes it possible to do this operation without the laborious manual labor required heretofore. It is also possible to use the machine for polishing the floor, merely by substituting polishing blocks for the sanding blocks and operating the machine in the same manner as described. In fact, because of the widely different types of operations possible therewith, this is a universal machine which can perform all such operations.

- The blocks 38 are operated in opposite directions so that the thrust of the respective blocks counteracts each other, which reduces the strain on the machine and on the operator. Moreover, itnot only applies a better finish to the floor by the more uniform sanding or finishing operation provided, but it also eliminates dust, dirt and i.

noise that have been so objectionable heretofore with other types of sanding machines.

Any suitable handle may be applied thereto for manipulation of the machine, back and forth over the floor. While the invention has been illustrated and described in one embodiment, it is recognized that variations and changes may be made therein without departin from the invention, except as specified in the claims.

I claim:

1. In a floor sanding machine, the combination with a pair of sanding heads mounted in side-byside relation, guides for the heads, crank means having connecting rods with the respective heads, power means operatively connected with the crank means for actuating the heads, a frame supporting the crank means and power means, wheels supporting the frame, speed-reducing means connecting the power means with the 10 crank means, and means operatively connecting the power means with the wheels for selectively driving the wheels in alternate directions and at variable speeds.

2. A floor sanding machine comprising a wheel supported base having a power unit mounted thereon, a drive shaft for said power unit, a friction wheel rigidly secured to one end of said drive shaft, a shaft rotatably mounted on said base, a friction wheel mounted on said last named shaft and having peripheral engagement with said first friction wheel, a cross shaft rotatably mounted on said base, a third friction wheel mounted on said cross-shaft intermediate its ends, means for selectively adjusting said third friction wheel on said cross-shaft relative to th longitudinal axis thereof, said third friction wheel having peripheral engagement with one face of said second friction wheel and being linearly adjustable along a diameter thereof, sprockets mounted on each end of said cross-shaft for rotation therewith, an axle rotatably mounted on said base and having said wheels affixed at each end thereof, a sprocket rigidly secured to said axle adjacent each of said wheels, endless chains interconnecting said sprockets on said cross-shaft with said sprockets on said axle, whereby adjustment of said third friction wheel longitudinally along said crossshaft to one or the other sides of the axis of said second friction wheel will drive said wheels clockwise or counter-clockwise at any selected speed, a plurality of elongated, laterally spaced, parallel guide members having one of their respective ends secured to said base, a pair of sanding heads slidably mounted intermediate adjacent pairs of said guide members, a second cross-shaft mounted on said base, an inertia wheel for each of said sanding heads, said inertia wheels being mounted adjacent each end of said second cross-shaft, a crank shaft pivotally connecting each of said sanding heads eccentrically with respect to its respective said inertia wheel, and means connecting said second cross-shaft in driving relationship with said power unit to rotate said inertia wheels.

3. A sanding head comprising a substantially rectangular base having a pair of opposed, spaced, parallel arms projecting upwardly therefrom, a pair of U-shaped brackets mounted and secured on said arms, said brackets extending transversely of said sanding head and being spaced from each other, a sandpaper dispensing shaft journaled between the arms of one of said U-shaped brackets and a sandpaper winding shaft journaled between the arms of the other of said U-shaped brackets, a ratchet wheel rigidly secured on each of said shafts for rotation therewith, a holding pawl for each of said ratchet wheels and normally in engagement therewith, means on one arm of each U-shaped bracket slidably supporting each of said pawls thereon for movement toward and away from said ratchet wheels, a ratchet for one of said ratchet wheels, said ratchet being pivotally mounted on an arm of said base and engaging said ratchet wheel, and timing means periodically disengaging said holding pawls from said ratchet wheels and actuating said ratchet to turn said one wheel through a portion of its circumference.

4. A floor sanding machine comprising a wheel supported base, power means mounted on said base, an inertia wheel mounted on each side of said base for rotation about a horizontal aXle, variable speed means connected between at least one wheel on each side of said machine and said power means whereby the rate of travel of said machine may be adjustably controlled, a plurality of spaced, parallel guidemeinbers projecting 'outwardly from said base, a sanding head mounted for reciprocation between each adjacent pair of guide members, a rod for each of said sandin heads, each of said rods having one of its ends pivotally connected With one end of its respective sanding head, and each of said rods having its respective other end eccentrically and pivotally connected with one of said inertia wheels.

5. A sanding head adapted to be reciprocally mounted between a pair of guide members of a sanding machine, said sanding head comprising a substantially rectangular base having a .pair of opposed, spaced, parallel arms projecting upwardly therefrom, a pair of U-shaped brackets mounted on and secured to said arms, said brackets extending transversely of said sanding head and being spaced from each other, a sand paper dispensing shaft journaled :for rotation in one of said U-shaped brackets, a sand paper winding shaft journaled in the other of said brackets, a ratchet wheel mounted on the adjacent ends of each of said shafts for rotation therewith, ajholding pawl for each of said ratchet wheels and normally in engagement therewith, a ratchet for each of said ratchet wheels, bell crank levers pivotally mounted on said arm of said sanding head adjacent said ratchet wheels, means connecting each end of one of said bell crank levers with said holding pawl and ratchet of each of said ratchet Wheels, respectively, means for rendering one or the other of said ratchets inoperative, and means connected to said bell crank lever and cooperating with means disposed on one of said guide members for pivotally actuating said bell crank levers to disengage said pawls from said ratchet wheel and to actuate the operative ratchet to turn one of said wheels through a portion of its circumference, said other ratchet being disengaged from its ratchet wheel and inoperative during such turning movement.

6. A sanding head reciprocally mounted between a pair of guide members of a sanding machine, said sanding head comprising a substantially rectangular base having a pair of opposed, spaced, parallel arms projecting upwardly therefrom, a pair of brackets mounted on and secured to said arms, said brackets being spaced from each other, a sand paper dispensing shaft journaled for rotation in one of said brackets, a sand paper winding shaft journaled in the other of said brackets, a ratchet wheel mounted on the adjacent ends of each of said shafts for rotation therewith, a holding pawl for each of said ratchet wheels and normally in engagement therewith, a ratchet'for each of said ratchet wheels, bell crank levers pivotally mounted on an arm of said sanding block adjacent saidratchet wheels, means connecting each end of one of said bell crank levers with said holding pawl and ratchet of each of said ratchet wheels, respectively, means for rendering one or the other of said ratchets inoperative, and means connected to said bell crank levers and cooperating with means disposed on one of said guide members for pivotally actuating said bell crank levers to disengage said pawls from said ratchet wheel and to actuate the operative ratchet to turn one of said wheels through a portion of its circumference, said other ratchet being disengaged from its ratchet wheel and inoperative during such turning movement.

7. A sanding head for a. sanding machine comprising a substantially rectangular base mounted for reciprocation between a pair of spaced guide members, a sand paper 'windingshaft and .a sand paper dispensing shaft, .means rotatablysupporting .said shafts on said head in spacedlparallel relationship, :a ratchet wheel mounted on the adjacent ends of each or said :sha'fts, a holdin pawl for. :each of said ratchet wheels and :normallyin engagement therewith, ra ratchet-foreadh of said ratchet wheels, a bell crank :lever pivotally supported on said head adjacent each of :said ratchet wheels, means "connecting each end of each of said bell crank levers with said pawl and said ratchet of said adjacent ratchet wheel, respectively, .means for rendering .one or the other of said ratchets 'inoperative,3and means pivotally connected to each of. said he'll icrank levers and coacting with means fixedly secured onone of said guide members to pivotally actuate said bell crank levers to disengage said 'pawls from said ratchet wheels and to actuate the operative ratchet to turn the ratchet-engaged ratchet wheel through apor-tion of its circumference, said other ratchet -being disengaged from its ratchet Wheel and inoperative during such turning movement.

8. A sanding head for a sanding machine comprising a substantially rectangular base mounted for reciprocation between a pair of spaced guide members, a sand paper windin shaft and 'asand paper dispensing shaft, means rotatably supporting said shafts on said head in spaced, parallel relationship, a ratchet wheel mounted on the ad'- jacent ends of each of said shafts, a holding pawl for each of said ratchet wheels and normally in engagement therewith, a ratchet for each of said ratchet wheels, a bell crank lever pivotally supported onsaid head adjacent each ofsaicl ratchet wheels, means connecting each end of each of said'bell crank levers with said pawl and said ratchet of said adjacent ratchet wheel, respectively, means for rendering one or the other' of said ratchets inoperative, and means pivotally connected to each of said bell crank levers and coacting with means mounted on one of said guide members and adjustable longitudinally thereof to pivotally actuate said ball crank levers to disengage said pawls from said ratchet wheels and to actuate the operative ratchet.

9. A sanding head for a sanding machine comprising a substantially rectangular base mounted for reciprocation between a pair of spaced guide members, a sand paper winding shaft and a sand paper dispensing shaft, means rotatably supporting said shafts on said block in spaced, parallel relationship, a ratchet wheel mounted on the adjacent ends of each of said shafts, a holding pawl for each of said ratchet wheels and normally in engagement therewith, a ratchet for each of said ratchet wheels, a bell crank lever pivotally supported on said head adjacent each of said ratchet wheels, means connecting each end of each of said bell crank levers with said pawl and said ratchet of each of said adjacent ratchet wheels, respectively, means for rendering one or the other of said ratchets inoperative, means pivotally connected to each of said bell crank levers and coacting with means fixedly secured on one of said guide members 'to pivotally actuate said bell crank levers to dis engage said pawls from said ratchet wheels and to actuate the operative ratchet to turn the ratchet engaged ratchet wheel through a portion of its circumference, said other ratchet being disengaged from its ratchet wheel and inoperative during such turning movement, and resilient means connected between said bell crank levers and said head to return said pawls into engagement with said ratchet wheels and to move said operative ratchet to its next operative position.

10. A sanding head for a sanding machine comprising a substantially rectangular base mounted for reciprocation between a pair of spaced guide members, a sand paper winding shaft, a sand paper dispensing shaft, means r0- tatably supporting said shafts on said block in spaced, parallel relationship, a ratchet wheel mounted on the adjacent ends of each of said shafts, a holding pawl for each of said ratchet wheels and normally in engagement therewith, a ratchet for each of said ratchet wheels, a bell crank lever pivotally supported on said head adjacent each of said ratchet wheels, means connecting each end of each of said bell crank levers with said pawl and said ratchet of said adjacent ratchet wheel, respectively, means for rendering one or the other of said ratchets inoperative, and means connected to each of said bell crank levers and coacting with means secured on one of said guide members to pivotally actuate said bell crank levers to disengage said pawls from said ratchet wheels and to actuate the operative ratchet to turn the ratchet engaged ratchet wheel through a portion of its circumference, said other ratchet being disengaged from its ratchet wheel and inoperative during such turning movement.

DANIEL MORTON ROSE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

